feat(src): added feature of saving single image

docs/src/sdk/data/save_single_image.rst

@@ -0,0 +1,52 @@
+.. _data_save_single_image:
+
+Save Single Image
+=============================
+
+Press "Space" "s" "S" to save image.
+
+Reference commands:
+
+.. code-block:: c++
+
+  api->Start(Source::VIDEO_STREAMING);
+
+  cv::namedWindow("frame");
+
+  std::int32_t count = 0;
+  std::cout << "Press 'Space' 's' 'S' to save image." << std::endl;
+  while (true) {
+    api->WaitForStreams();
+
+    auto &&left_data = api->GetStreamData(Stream::LEFT);
+    auto &&right_data = api->GetStreamData(Stream::RIGHT);
+    if (!left_data.frame.empty() && !right_data.frame.empty()) {
+      cv::Mat img;
+      cv::hconcat(left_data.frame, right_data.frame, img);
+      cv::imshow("frame", img);
+    }
+
+    char key = static_cast<char>(cv::waitKey(1));
+    if (key == 27 || key == 'q' || key == 'Q') {  // ESC/Q
+      break;
+    } else if (key == 32 || key == 's' || key == 'S') {
+      if (!left_data.frame.empty() && !right_data.frame.empty()) {
+        char l_name[20];
+        char r_name[20];
+        ++count;
+        snprintf(l_name, sizeof(l_name), "left_%d.jpg", count);
+        snprintf(r_name, sizeof(r_name), "right_%d.jpg", count);
+
+        cv::imwrite(l_name, left_data.frame);
+        cv::imwrite(r_name, right_data.frame);
+
+        std::cout << "Saved " << l_name << " " << r_name << " to current directory" << std::endl;
+      }
+    }
+  }
+
+  api->Stop(Source::VIDEO_STREAMING);
+
+The above code uses OpenCV to display the image. When the display window is selected, pressing ``ESC/Q`` will end the program.
+
+Complete code examples, see `save_single_image.cc <https://github.com/slightech/MYNT-EYE-S-SDK/blob/master/samples/tutorials/data/save_single_image.cc>`_ .

samples/tutorials/CMakeLists.txt

@@ -112,6 +112,7 @@ make_executable2(get_imu_correspondence
   WITH_OPENCV
 )
 make_executable2(get_imu SRCS data/get_imu.cc util/cv_painter.cc WITH_OPENCV)
+make_executable2(save_single_image SRCS data/save_single_image.cc WITH_OPENCV)
 make_executable2(get_from_callbacks
   SRCS data/get_from_callbacks.cc util/cv_painter.cc
   WITH_OPENCV

samples/tutorials/data/save_single_image.cc

@@ -0,0 +1,55 @@
+#include <stdio.h>
+#include <opencv2/highgui/highgui.hpp>
+
+#include "mynteye/api/api.h"
+
+MYNTEYE_USE_NAMESPACE
+
+int main(int argc, char *argv[]) {
+  auto &&api = API::Create(argc, argv);
+  if (!api) return 1;
+
+  bool ok;
+  auto &&request = api->SelectStreamRequest(&ok);
+  if (!ok) return 1;
+  api->ConfigStreamRequest(request);
+
+  api->Start(Source::VIDEO_STREAMING);
+
+  cv::namedWindow("frame");
+
+  std::int32_t count = 0;
+  std::cout << "Press 'Space' 's' 'S' to save image." << std::endl;
+  while (true) {
+    api->WaitForStreams();
+
+    auto &&left_data = api->GetStreamData(Stream::LEFT);
+    auto &&right_data = api->GetStreamData(Stream::RIGHT);
+    if (!left_data.frame.empty() && !right_data.frame.empty()) {
+      cv::Mat img;
+      cv::hconcat(left_data.frame, right_data.frame, img);
+      cv::imshow("frame", img);
+    }
+
+    char key = static_cast<char>(cv::waitKey(1));
+    if (key == 27 || key == 'q' || key == 'Q') {  // ESC/Q
+      break;
+    } else if (key == 32 || key == 's' || key == 'S') {
+      if (!left_data.frame.empty() && !right_data.frame.empty()) {
+        char l_name[20];
+        char r_name[20];
+        ++count;
+        snprintf(l_name, sizeof(l_name), "left_%d.jpg", count);
+        snprintf(r_name, sizeof(r_name), "right_%d.jpg", count);
+
+        cv::imwrite(l_name, left_data.frame);
+        cv::imwrite(r_name, right_data.frame);
+
+        std::cout << "Saved " << l_name << " " << r_name << " to current directory" << std::endl;
+      }
+    }
+  }
+
+  api->Stop(Source::VIDEO_STREAMING);
+  return 0;
+}